My friends over in the Office 365 team have provided some guidance on their community site about preparing for daylight saving time changes around the world…
If the country or region where your organization or some of your users reside has changed their policy of recognizing daylight saving time, or changed the local time offset from Coordinated Universal Time (UTC), you need may need to update Windows, Exchange, Outlook, or other programs to accommodate these changes.
Even if your time zone hasn't changed, if you interact with other computers or users globally, your computer needs to be able to do accurate date and time calculations for events elsewhere in the world.
Installing the time zone updates as soon as possible minimizes the number of Outlook and Exchange meetings or calendar events that are scheduled during the transition from the old to the new time and dates.
More info available in their post.
Also available via http://bit.ly/paBiNH